Dual crankshaft internal combustion engine

ABSTRACT

A pair of crankshafts is rotatively mounted in a crankcase and carries respectively at the ends thereof pairs of intermeshing gears for synchronizing the shafts. A reciprocating piston in a cylinder carries a main connecting rod. A pair of subconnecting rods is rotatively secured to each other and to the lower end of the main connecting rod, which subconnecting rods are respectively secured to the cranks and the crankshafts.

United States Patent 1 1 Aug. 1,1972

Healy [54] DUAL CRANKSHAFT INTERNAL COMBUSTION ENGINE I [72] Inventor: Elton F. Healy, 6 Chace Ave., Warren, R1. 02885 [22] Filed: Sept. 4, 1970 21 App1.No.: 69,564

[52] US. Cl ..74/44 [51] Int. Cl ..Fl6h 21/22 [581 Field of Search.....74/44, 579, 603, 13, 15, 15.2; 123/58 [56] References Cited UNITED STATES PATENTS 1,341,709 6/1920 Dodge et a1 ..74/44 2,417,910 3/1947 Bruegger ..74/44 2,392,921 l/1946 Holman ..74/44 Primary Examiner-William F. ODea Assistant Examiner-Wesley S. Ratliff, Jr. Attorney-Prangley, Dithmar, Vogel, Sandler & Scotland [5 7] ABSTRACT A pair of crankshafts is rotatively mounted in a crankcase and carries respectively at the ends thereof pairs of intermeshing gears for synchronizing the shafts. A reciprocating piston in a cylinder carries a main connecting rod. A pair of subconnecting rods is rotatively secured to each other and to the lower end of the main connecting rod, which subconnecting rods are respectively secured to the cranks and the crankshafts.

9 Claims, 5 Drawing Figures INVENTOR ELTON F HEALY ATTO RNEYS P'A TENTEMB 1 I912 3.680.396

SHEET 2 I]? 2 INVENTOR ELTON F. HEALY DUAL CRANKSIIAFT INTERNAL COMBUSTION ENGINE It is an important object of the present invention to provide an internal combustion engine which has two crankshafts synchronously rotated in opposite directions by means of a piston-cylinder arrangement.

A further object of the present invention is to construct the connecting rods for a dual crankshaft internal combustion material in such a manner as to prevent deformation thereof during operation.

Another object of the invention is to improve the dynamic balance of a dual crankshaft internal combustion engine by providing flywheels on the crankshafts respectively at the opposite ends thereof.

A yet further object of the invention is to enable use of ,two large flywheels on a dual crankshaft internal combustion engine.

Further features of the invention pertain to the particular arrangement of the parts of the internal combustion engine, whereby the above-outlined and additional operating features thereof are retained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary view of the ends of a crankcase, the crankshafts therein, and the associated components;

FIG. 2 is a vertical cross-sectional view of a cylinderpiston arrangement for driving the cranks of the crankshafts shown in FIG. 1;

FIG. 3 is a top plan view of the connecting rod assembly for transmitting the reciprocating motion of the piston to the crankshafts;

F IG. 4 is a view in yertical section along the line 4-4 of FIG. 3; and

FIG. 5 illustrates the construction of one of the subconnecting rods.

Referring now to the drawings, and more particularly to FIG. 1 thereof, there is shown a crankcase which is part of an internal combustion engine. As can be seen, there are shown only the end portions of the crankcase 10 and the associated components. Rotatively mounted in the crankcase 10 is a pair of crankshafts and which are essentially duplicates of one another, but are arranged to be 180 out of phase with each other. The crankshaft. 20 includes a crank 21 and is mounted for rotation by means of bearings 22. The crankshaft 20 has a longer end portion 20a at one end, which protrudes from the rear (to the left as viewed in FIG. 1) of the crankcase 10. A helical gear 23 is carried by the crankshaft 20 near one end thereof, which gear 23 is keyed to the crankshaft 20 so as to rotate therewith. Similarly, a helical gear 24 is carried by the crankshaft 20 adjacent to the opposite end thereof. Oil seals 25 and 26 are provided. A flywheel 27 is mounted on the protruding end portion 20a and is keyed thereto.

crankshaft 30 in horizontal alignment with the gear 24 and in meshing engagement therewith. The gears 33 and 34 are keyed to the crankshaft 30 so as to rotate therewith. Oil seals 35 and 36 are provided. The shaft 30 has an end portion 30a which protrudes from the front (to the right as viewed in FIG. 1) of the crankcase 10, which portion 30a carries a flywheel 37 and a sheeve 38 having a plurality of V-grooves therein. Both the flywheel 37 and the sheeve 38 are keyed to the shaft portion 30a. V-belts or the like are used to transmit the rotation of the sheeve 38 to other power-req uiring elements of the vehicle, such as the alternator.

Referring now to FIGS. 2 through 5, there follows a description of the details of construction of the mechanism by which the crankshafts 20 and 30 are rotated. Said mechanism includes a cylinder 40 within which is reciprocably mounted a piston 41. Around the periphery of the piston 41 are the usual annular grooves carrying piston rings 42. A pair of spaced, apertured flanges 43 depends from the piston 41. A main connecting rod 50 of I-beam construction has at one end portion 51 an aperture therethrough. A wrist pin 52 passes through the apertures in the flanges 43 and through the aperture in the end portion 51. The connecting rod 50 has at the opposite end thereof an apertured flange 53.

There is further provided a pair of subconnecting rods 60 and 70. As is best seen in FIG. 5, the connecting rod 60 has a pair of spaced flanges 61, each having an aperture 62 therethrough. The other end of the subconnecting rod 60 is of the usual construction and has a bearing element 63 which is connectable to a second bearing element 64 by means of fasteners 65. Theother subconnecting rod is of substantially the same construction, having a pair of spaced apertured flanges 71 at one end and a bearing element 73 at the other end. A matching bearing element 74 is also provided. The distance between the flanges 61 is equal to the distance between the flanges 71 and the flanges are individually about the same thickness. The distance between the respective pairs of flanges 61 or 71 is equal substantially to the sum of the thickness of the flange 53 on the main connecting rod 50, plus the thickness of a flange on the subconnecting rods. Thus, the connecting rods 50, 60 and 70 may be interfitted as shown in FIG. 4 into an arrangement where the flange 53 is centrally disposed and the flanges on each of the subconnecting rods enclose both the flange 53 and one flange on the other subconnecting rod. A wrist pin 77 passes through the aligned apertures in the flanges 53, 61, and 71 in such a manner to enable the subconnecting rods 60 and 70 to rotate independently about the axis of the wrist pin 77.

The bearing elements 63 and 64 may be used in connecting the subconnecting rod 60 to the crank 21 of the crankshaft 20. Similarly, the bearing elements 73 and 74 may be used to connect the subconnecting rod 70 to the crank 31 of the crankshaft 30.

The piston 41 is reciprocated within the cylinder 40 in the usual manner in turn to reciprocate the main connecting rod 50. The subconnecting rods 60 and 70 rotate the cranks 21 and 31 as indicated by the arrows and the dotted line showings. The cranks 21 and 31, of course, move in opposite directions, whereby one of the crankshafts rotates in a clockwise direction, and the other crankshaft rotates in a counterclockwise direction. The crankshaft 20 operates the transmission by means of a connection to the power take-off member 28. The crankshaft 30 operates the alternator and other accessories.

The intermeshing gears adjacent the corresponding ends of the crankshafts 20 and 30 synchronize the two crankshafts so they rotate at the same speed and are at related angular positions at any instant of time, despite variations in the output requirements of the two crankshafts. Placing one flywheel 27 at the'rear and one flywheel 37 at the front improves the front-to-rear dynamic balance. Moreover, by placing the flywheels 27 and 37 at opposite ends of the crankcase the size of the flywheels can be as desired. For example, there is nothing at the rear of the crankshaft 30 to interfere with use of a larger flywheel 27 than that shown. The use of pairsof intermeshing gears is particularly desirable in maintaining synchronism between the two crankshafts and 30, even in the presence of the widely varying loads that may occur.

Although the power take-off member 28 has been shown to be mounted on the crankshaft 20 and the sheeve 38 for accessories is mounted on the other crankshaft 30, it is to be understood that if a reverse motion is desired, the power take-off member 28 may be mounted on the crankshaft 30 and the sheeve 38 for accessories mounted on the crankshaft 20.

The use of connecting rods 50, 60 and 70 having an I-beam construction is particularly significant in minimizing the chances of these parts being deformed during extended operation. It should be readily appreciated that tremendous forces are continuously being exerted on these connecting rods. It has been found however that this type 'of construction has particular ability to withstand bending forces during use.

The particular arrangement of interconnecting the con-- necting rods 50, 60, and 70 by means of the flanges 53, 61, and 71 guides the main connecting rod in essentially vertically reciprocable movement without any further guiding means.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that variousv modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true scope and spirit of the invention.

What is claimed is:

1. In an internal combustion engine, the combination comprising a crankcase, two crankshafts mounted for rotation in said crankcase, a first fly wheel at one end of one of said crankshafts, a second fly wheel at the other end of the other of said crankshafts, a first pair of intermeshing gears respectively on said crankshafts near the corresponding ends thereof and keyed thereto, a second pair of intermeshing gears respectively on said crankshafts near the opposite corresponding ends thereof and keyed thereto, said first and second pairs of intermeshing gears being operative to synchronize said crankshafts substantially independently of the loads thereon, a cylinder mounted adjacent to said crankcase, a reciprocating piston in said cylinder, a main connecting rod secured at one end thereof to said piston, a pair of subconnecting rods rotatively secured to each other for rotation about a common axis and to the other end of said main connecting rod, the free crankshafts for transmitting power to the other powerrequiring elements of the vehicle.

3. In the internal combustion engine of claim I, v 1

wherein each of said gears is of the helical type.

v 4. In an internal combustion engine of claim 1,:

wherein one of said crankshafts has a first end portion protruding from one end of said crankcase, the other of said crankshafts having a second end portion protruding from the other end of said crankcase, said first and second flywheelsbeing respectively disposed onsaid first end portion andsaid second end portion of said crankshafts.

5. In an internal combustion engine, the combination comprising a crankcase, two crankshafts mounted for rotation in said crankcase, a first flywheel at one end of one of said crankshafts, a second flywheel at the other end of the other of said crankshafts, a cylinder mounted adjacent to said crankcase, a reciprocating piston in said cylinder, a mainconnecting rod secured at one end thereof to said piston and having an apertured flange at the other end thereof, a pair of subconnecting rods operatively secured at corresponding ends thereof respectively to the cranks on said crankshafts, each of said crankshafts having on the other end thereof a pair. of spaced flanges with an aperture therein, said flanges on one of said subconnecting rods interfitting with said flanges on the other of said subconnecting rods and with said flange on said main connecting rod, a wrist pin passing through the apertures in all of said flanges to enable said subconnecting rods each to rotate independently about the axis of said wrist pin. v

6. In the internal combustion engine of claim 5, wherein said piston has depending therefrom a pair of spaced apertured flanges, said main. connecting rod having means at one end thereof with an aperture aligned with the apertures in said dependent flanges, and further comprising a wrist pin passing through the aperture in said main connecting rod and the apertures in said depending flanges.

7. In the internal combustion engine of claim 5, wherein said main connecting rod and each of said subconnecting rods are of l-beam construction.

8. In the internal combustion engine of claim 5, wherein the spacing between said flanges on each of said subconnecting rods is slightly greater than the sum of the thickness of the flange on said main connecting rod plug the thickness of the flange on said main connecting rod plus the thickness of one of said flanges of a subconnecting rod, one flange on one of said subconnecting rods and the flange, on said main connecting rod being disposed between the flanges on the other of said subconnecting rods, one flange on said other subconnecting rod and the flange on said main connecting rod being disposed between the flanges on said one connecting rod.

9. In an internal combustion engine, the combination comprising a crankcase, two crankshafts mounted for rotation in said crankcase, a first pair of intermeshing gears respectively. on said'crankshafts near the corresponding ends thereof vand keyed thereto, a second pair of intermeshing gears respectively on said crankshaft near the opposite corresponding ends thereof andkeyed thereto, said first and second pairs of intermeshing gears being operative to synchronize said crankshafts substantially independently of the loads thereon, a first fly wheel at one end of one of said crankshafts, a second fly wheel at the other end of the UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,680,396 7 Dated Angnqr-J iQJ? In e it n-( ELTON F. HEALY It is certified that error appears in the above-identified patent and that said-Letters Patent are hereby corrected as shown below:

Col 4, Claim 8, line 57, "plug" should be plus I I line 57, after "of", i u insert one of said flanges on a I subconnecting rod, one flange on one of said subconnecting rods and line 59, delete "one of said" and insert said other line 60, delete beginning with "and" v and through line 61.

line 62, delete "said subconnecting rods,

Signed and sealed this 20th day of March 1973 (SEAL) Attest EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 60376-P69 Q U.5. GOVERNMENT PRINTING OFFICE: 1969 0-356334 

1. In an internal combustion engine, the combination comprising a crankcase, two crankshafts mounted for rotation in said crankcase, a first fly wheel at one end of one of said crankshafts, a second fly wheel at the other end of the other of said crankshafts, a first pair of intermeshing gears respectively on said crankshafts near the corresponding ends thereof and keyed thereto, a second pair of intermeshing gears respectively on said crankshafts near the opposite corresponding ends thereof and keyed thereto, said first and second pairs of intermeshing gears being operative to synchronize said crankshafts substantially independently of the loads thereon, a cylinder mounted adjacent to said crankcase, a reciprocating piston in said cylinder, a main connecting rod secured at one end thereof to said piston, a pair of subconnecting rods rotatively secured to each other for rotation about a common axis and to the other end of said main connecting rod, the free ends of said subconnecting rods being operatively secured respectively to the cranks on said crankshafts.
 2. In the internal combustion engine of claim 1, the combination further comprising means on one of said crankshafts for transmitting the rotation thereof to the wheels of a vehicle, and means on the other of said crankshafts for transmitting power to the other power-requiring elements of the vehicle.
 3. In the internal combustion engine of claim 1, wherein each of said gears is of the helical type.
 4. In an internal combustion engine of claim 1, wherein one of said crankshafts has a first end portion protruding from one end of said crankcase, the other of said crankshafts having a second end portion protruding from the other end of said crankcase, said first and second flywheels being respectively disposed on said first end portion and said second end portion of said crankshafts.
 5. In an internal combustion engine, the combination comprising a crankcase, two crankshafts mounted for rotation in said crankcase, a fiRst flywheel at one end of one of said crankshafts, a second flywheel at the other end of the other of said crankshafts, a cylinder mounted adjacent to said crankcase, a reciprocating piston in said cylinder, a main connecting rod secured at one end thereof to said piston and having an apertured flange at the other end thereof, a pair of subconnecting rods operatively secured at corresponding ends thereof respectively to the cranks on said crankshafts, each of said crankshafts having on the other end thereof a pair of spaced flanges with an aperture therein, said flanges on one of said subconnecting rods interfitting with said flanges on the other of said subconnecting rods and with said flange on said main connecting rod, a wrist pin passing through the apertures in all of said flanges to enable said subconnecting rods each to rotate independently about the axis of said wrist pin.
 6. In the internal combustion engine of claim 5, wherein said piston has depending therefrom a pair of spaced apertured flanges, said main connecting rod having means at one end thereof with an aperture aligned with the apertures in said dependent flanges, and further comprising a wrist pin passing through the aperture in said main connecting rod and the apertures in said depending flanges.
 7. In the internal combustion engine of claim 5, wherein said main connecting rod and each of said subconnecting rods are of I-beam construction.
 8. In the internal combustion engine of claim 5, wherein the spacing between said flanges on each of said subconnecting rods is slightly greater than the sum of the thickness of the flange on said main connecting rod plug the thickness of the flange on said main connecting rod plus the thickness of one of said flanges of a subconnecting rod, one flange on one of said subconnecting rods and the flange on said main connecting rod being disposed between the flanges on the other of said subconnecting rods, one flange on said other subconnecting rod and the flange on said main connecting rod being disposed between the flanges on said one connecting rod.
 9. In an internal combustion engine, the combination comprising a crankcase, two crankshafts mounted for rotation in said crankcase, a first pair of intermeshing gears respectively on said crankshafts near the corresponding ends thereof and keyed thereto, a second pair of intermeshing gears respectively on said crankshaft near the opposite corresponding ends thereof and keyed thereto, said first and second pairs of intermeshing gears being operative to synchronize said crankshafts substantially independently of the loads thereon, a first fly wheel at one end of one of said crankshafts, a second fly wheel at the other end of the other of said crankshafts, a cylinder mounted adjacent to said crankcase, a reciprocating piston in said cylinder, a main connecting rod secured at one end thereof to said piston, a pair of subconnecting rods rotatably secured to each other and to the other end of said main connecting rod, the free ends of said subconnecting rods being operatively secured respectively to the cranks on said crankshafts. 